tkinter deforms my frames after inserting objects

Question

So I want to insert some objects in a frame, but when I firstly added a button the frames where were they weren't suppoused to.

Before
After

And this is the code:

import tkinter as tk

root = tk.Tk()
root.geometry("1200x700")

# Main frames
frame1 = tk.Frame(root, width=1200, height=625)
frame2 = tk.Frame(root, width=1200, bg="black", height=75)

frame1.grid(row=1, column=1)
frame2.grid(row=2, column=1)

# Secondary frames
frame1browser = tk.Frame(frame1, height=625, width=850, bg="grey")
frame1a = tk.Frame(frame1,height=625, width=(1200-850))

frame1browser.grid(row=1, column=1)
frame1a.grid(row=1, column=2)

# Last frames
frame1aa = tk.Frame(frame1a, width=(1200-850),height=525, bg="green")
frame1ab = tk.Frame(frame1a, width=(1200-850),height=100, bg="yellow")

frame1aa.grid(row=1, column=1)
frame1ab.grid(row=2, column=1, sticky="nswe")

# Elements that are not frames
Button1 = tk.Button(frame1ab, text="ur mother")
Button1.grid(column=1, row=1)

root.mainloop()

Answer 1

The frame ignores the width/height explicitly given if there is a widget inside it, by default. AFAIK, It finds and uses the minimum size required to fit all the widgets, also accommodating to extra properties like sticky , expand and so on.

To override this behavior, you will have to use the <grid/pack>_propagate(False) depending on whether you use pack or grid on the items inside the frame. Now the frame will grow/shrink as much as the size you specify.

frame1ab.grid_propagate(False)